In nature, a series of microbial processes of degradation of organic matter occur, in some cases via pathways different from aerobic oxidative combustion or from anaerobic digestion, in which processes different microbes which act symbiotically generally participate. Advantage may be taken of some of these natural processes, appropriately directed, in order to obtain new products by fermentative biological means.
Among these symbiotic processes, there is one in which two types of bacteria mainly participate, the bacteria in question being lactic bacteria, such as lactobacilli and streptococci, which produce lactic acid from hydrocarbon chains, as in carbohydrates, and other bacteria, of the genus Desulfovibrio, which use the lactic acid produced by the above bacteria as a primary energy source, and the anionic sulphur groups-which, in this biological process, bind to the carbohydrates-as a secondary energy source. Thus, in one phase of the process, sulphur-containing hydrocarbon chains are produced. Specifically, while on the one hand the Desulfovibrio profit from the lactic acid produced by the lactic bacteria, the latter in turn profit from a series of biotic components which stimulate their growth and metabolism, the most important of these being specifically these sulphur-containing carbohydrates, which represent potent activators of lactic bacteria, likewise acting to stabilize and protect these bacteria from oxidizing products, peroxides, and the like, which are produced in the process.
The subject of this patent is hence the use of this natural process for the production of these compounds which activate lactic fermentation, sulphur-containing carbohydrates, but with a careful adjustment of its working conditions in order to direct this fermentation optimally towards the production of these compounds in an acceptable yield.
It is extremely well known that lactic bacteria, mainly lactobacilli and streptococci, in addition to participating in many natural processes, have been used for thousands of years for obtaining fermented foods, including milk products, sausages, pickles and olives, apart from the production of lactic acid, so that no special explanation regarding them is required.
On the other hand, bacteria of the genus Desulfovibrio, of which the most important species is the species Desulfovibrio desulfuricans, are little known despite their abundance, and were discovered by Beijerinck who, in 1885, described their metabolism and properties. The most important subsequent publication was that of Baars, J. K., in 1930, over Sulfataat reductie door Bacterien. W. D. Meinema, N. V. Delft, Holland, nothing important having been published about them since then. They are saprophytic bacteria which are found in abundance in decomposing topsoils, humus, sewage and seafloor sludges. They are completely harmless bacteria for man and animals, in whose bodies the substrate and conditions which they require are impossible to find. They are very ancient bacteria which have evolved very little, that is to say they are stable from the genetic standpoint, which makes them resistant to possible mutations which might give rise to anomalous processes. For this process, special strains have been isolated, which have confirmed the regularity and constancy of their characters over numerous generations, so there are no problems of degeneration with time, as occurs with other bacteria, including lactic bacteria. Specifically, an important action of Desulfovibrio is to protect lactic bacteria from their degradation, attack by phage and mutations.
The novelty of this invention is specifically the use of fermentative biological means for obtaining this type of compound, since reactions employing chemical means (synthesis) which can produce them have been known since the last century. The vulcanization of rubber, discovered by Goodyear in 1839, by inserting sulphur atoms in the hydrocarbon chains of rubber, was the first. Subsequently, in the solubilization of cellulose for obtaining rayon, other processes using carbon disulphide to supply sulphur to the cellulose were invented. Many reactions of this kind are to be found in the literature of the beginning of the present century. The biological means used in this invention represents a natural process, within an ecological order.